Exhaust Gas Temperature Sensor Circuit Bank 1 Sensor 2
Diagnostic trouble code P2031 indicates that the powertrain control module (PCM) has detected an abnormal voltage or resistance signal from the exhaust gas temperature (EGT) sensor located in Bank 1, Sensor 2. This means the sensor's circuit is malfunctioning, preventing the PCM from accurately monitoring the exhaust temperature downstream of the catalytic converter or diesel particulate filter.
While this code rarely causes immediate drivability issues, ignoring it can lead to inefficient emissions system operation and potential damage to the catalytic converter or DPF over time.
Common symptoms
- Illuminated Check Engine Light
- Decreased fuel efficiency
- Failed emissions test
- Incomplete diesel particulate filter (DPF) regeneration (on diesel engines)
- No noticeable drivability symptoms in many cases
Likely causes
- Faulty Exhaust Gas Temperature (EGT) sensor (Bank 1, Sensor 2)
- Damaged, burnt, or corroded wiring in the EGT sensor circuit
- Loose or corroded electrical connector at the EGT sensor
- Severe exhaust leak near the EGT sensor
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Visually inspect the EGT sensor and its wiring harness.
Look for: Look for burnt, chafed, or melted wires, as well as a loose or heavily corroded connector, which are common due to the high heat of the exhaust system.
Check the EGT sensor connector for proper voltage and ground.
Look for: Using a multimeter, verify that the PCM is supplying the correct reference voltage (usually 5V) and a solid ground to the sensor connector with the key on, engine off.
Measure the internal resistance of the EGT sensor.
Look for: Disconnect the sensor and measure its resistance with a multimeter. Compare the reading to the manufacturer's specifications; an open circuit (infinite resistance) or a short indicates a failed sensor.
Inspect the exhaust system for leaks near the sensor.
Look for: Listen for exhaust ticking or look for soot marks around the exhaust pipes and joints near Bank 1 Sensor 2, which could skew the temperature readings.
Monitor the EGT sensor data via a scan tool.
Look for: Observe the live data for Bank 1 Sensor 2 EGT. The temperature should rise smoothly as the engine warms up. If the reading is stuck at an extreme value (e.g., -40 degrees or 1800 degrees) or fluctuates erratically, the circuit or sensor is faulty.
This page explains the generic P2031 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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